Images of a structure of an object are generated in one of a number of conventional modalities. In medical care, where the object is a patient, the images are suitable for diagnostic purposes or radiotherapy treatment, or for planning surgery.
Examples of the conventional modalities include conventional X-ray plane film radiography, computed tomography (CT) imaging, magnetic resonance imaging (MRI), and nuclear medicine imaging techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT).
A three-dimensional (3D) medical image is a collection of adjacent (transaxial) two-dimensional (2D) slices. Clinicians recombine anatomical elements of 2D slices to form a 3D image of an anatomical region or an organ. This recombination process is usually termed reconstruction.
During clinical diagnosis, the patient's internal anatomy is imaged to determine how a disease has progressed. The infected tissues show some differences from normal tissues. Also, the patient may have some type of individual differences or abnormalities regarding healthy tissues.
The clinicians identify and handle critical anatomical regions, and in particular organs, on several images for planning of treatment or surgery. Handling critical anatomical regions and organs includes tracing the outline of these regions and organs, which yields graphical objects. A graphical object visually marks for the clinician the separation of an anatomical region from the other parts of an image. Manually drawing the individual contours on a contiguous set of 2D slices then combining them is very time consuming and labor intensive. The time and labor increases significantly with the number of image slices, the number and sizes of the organs, tumors, etc. in the anatomical area of interest. The quality of the contouring and 3D visual graphical objects generated from the 2D slices depends on the resolution and contrast of the 2D images, and on the knowledge and judgment of the clinician performing the reconstruction. However, conventional methods of segmentation of anatomical regions and organs by the clinician require a considerable amount of time to be performed and subjectivity in the judgment of the clinician in manual segmentation introduces a high degree of imprecision.
The graphical objects also need to be managed. Conventional methods of managing the graphical objects are inefficient and overwhelming to the abstraction skills of human clinicians.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for more efficient methods and apparatus of managing graphical objects. There is also need to reduce the time and imprecision of human clinicians in segmenting anatomical regions.